Screw-propeller.



No. 691,792. Patented Jan 28. I902.

F. c. METZ.

SCREW PROPELLER.

(Application filed Apr. 10, 1901.)

(No Model.)

THE "ohms maps co, vnomljma, WASHINGTON D. c.

UNITED STATES PATENT OFFICE.

FRANK O. lVlETZ, OF ALLEGHENY, PENNSYLVANIA.

SCREW-PROPELLER.

SPECIFICATION forming part of Letters Patent .No. 691,792, dated January 28, 1902. Application filed April 10, 1901. Serial No. 55,194. (No model.)

To all whom it may concern:

Be it known that I, FRANK C. METZ, a resident of Allegheny, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Screw-Propellers; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to propellers for steam vessels and similar uses; and its object is to provide a propeller havinga greater efficiency than propellers heretofore made.

In the ordinary propeller the shaft is' provided either With a continuous spiral blade or with several blades arranged spirally with reference-to the axis of the shaft. In either form all parts of the blade or blades bear the same angular relations to the axis of the shaft, and consequently each portion of the blade or blades cuts the Water at an angle. I have discovered, however, that if a portion or pertions of the blade or blades be made to lie substantially at right angles or perpendicular to the axis of the shaft and the adjacent portion or portions of the same blade be inclined with reference thereto so as to extend spirally with reference to the axis of the shaft the efficiency of the propeller will be greatly increased, the straight or perpendicular portion or portions of the blade cutting the water at right angles to the axis of the shaft and in that way securing a strong hold on the water, and the adjacent inclined portion or portions of the blade passing against the comparatively large body or wall of water thus formed meet with a strong resistance which gives said blades a strong forward thrust, and thereby a greater forward movement of the propeller or vessel is insured.

In the accompanying drawings, Figure lis a side view of my improved propeller, and Fig. 2 is an end view thereof.

1 represents the propeller-shaft, which is or may be of the ordinary construction, and preferably is tapered, as shown, and suitably secured to this shaft is the spiral blade 2, which blade, however, instead of forming a continuous uniform spiral around the shaft is provided with portions 3, which extend practically at right angles to the axis of the shaft or straight around the same and with the inclined or spiral portions 4, which preferably are arranged at substantially an angle of forty-five degrees to the axisof the shaft. The straightand spiral orinclined portions of the blade alternate with each other, and, as illustrated, they are each of a length to pass around substantially one-third of the circumference of the shaft, so that the straight and inclined portions of the blade alternate with each other, not only spirally about the shaft, but also longitudinally thereof, whereby a more evenly balanced propeller is secured. It is obvious, however, that the straight and spiral portions may extend for either more or less than one-third circumference of the propeller-shaft without departing from myinvention and that the inclined portions 4 may stand at an angle either more or less than forty-five degrees to the axis of the shaft.

My invention is equally applicable to the ordinary propeller-blades, in which case each of these blades will be provided with a portion which is at right angles to the axis of the shaft and an adjacent inclined portion which is at an angle preferably forty-five degrees thereto.

, In the use of my propeller the straight portion or portions 3 of the blades out the water at right angles to the axis of the shaft, and in the further rotation of the shaft the inclined portion or portions 4: bear against the wall of water thus formed by the straight portions, and therefore have exerted upon them a greater thrust than is the case with the ordinary screw-propeller.

What I claim as my invention, and desire to secure by Letters Patent, is-- 1. In a propeller, the combination of a shaft and a blade thereon, said blade having a portion or portions of its working face in a plane approximately at right angles to the axis of the shaft and another portion or portions thereof at an angle thereto.

2. In a propeller, the combination of ashaft and a blade thereon, said blade extending spirally about the shaft and changing its course at each one-third of the circumference of the shaft.

3. In apropeller, the combination of a shaft and a blade thereon, said blade changing its course at each one-third of the circumference of the shaft, alternate ones of said portions being in a plane substantially at right angles to the axis of the shaft and the others being \Vitnesses:

arranged at approximately an angle of fortyl ROBERT C. TOTTEN, five degrees thereto.

'METZ, have hereunto set my hand.

FRANK C. METZ.

G. KREMER.

In testimony whereof I, the said FRANK C. 

